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Is it Safe to Spray Your Engine with Water?


If you own a car, it’s your responsibility to take care of it. You have to clean it regularly and take it to the service station. Talking about the car wash, is it safe to spray your engine with water?

The answer depends on what type of engine is sitting in your car. If it’s the old-school one with everything metal and mechanical, you should avoid directly spraying the engine with water. Plus, you have to stay vigilant, especially when the engine’s temperature is high.

This post will guide you on how and when to wash your car’s engine.

Why is Water Risky to Car Engines?

You already know that electrical components and water don’t get along. The reason is simple: water is a good conductor of electricity, and when the water’s impurities come into contact with a device’s contact points, they tend to destroy the whole device.

No doubt, technological advancement has covered almost all the major industries, including automobiles.

Nowadays, you can find numerous electronic control boards inside almost every vehicle. Even the pre-1990 models had electrical components in their engines. Therefore, it’s not wise to pick up a water pipe and start spraying the engine bay. That might cost you good money in the end.

We’ll talk about the electronic engines later. First, let’s talk about mechanical engines.


Mechanical Engines

Before 1980, the majority of cars had complete mechanical engines. The inside of the engine consists of the following parts:

However, you might not see some or all the above parts in today’s electronic car. It doesn’t mean that modern cars run without them. The main parts of a car are hidden in a protective sealed box. You just can’t see them.

But things were different before 1980 in the automobile industry.

You have easy access to see the whole car’s engine after opening up the bonnet. From the big engine box to all other metal and mechanical components, almost everything was in front of you.

Such exposure had various disadvantages as well.

One of the biggest cons of having a totally open mechanical engine was water can easily damage each component of your car’s engine. That’s right.

How Does Water Damage Car’s Engines?

Chemically, water also doesn’t get along with metallic objects. The chemistry of soft water corrodes metal and steel more than hard water.

If you look inside the engine bay of old cars, you will see that almost every part is exposed. Even the electrical components such as the battery, coolant, and lights got wires that are prone to get wet.

No doubt, the engine gets cleaned when you spray water on it. However, it’s the nature of water to stick to objects and react.


If the engine’s parts don’t have the anti-rust coating on them, spraying water will clean them as well as shorten their lifespan.

Moreover, electrical connection points like battery terminals are also vulnerable. When the water reaches these points, it might create a spark or stay there until it dries off.

So it’s better to follow a car wash guideline before spraying water directly on the engine bay. We’ll see how to wash the car’s engine later in this post.

Electronic Engines

Although the hybrid models of cars have electronic components installed, other basic parts are still there, like filters, valves, and shafts. However, the only difference is that the newer models, call them post-‘90s, have the internal components covered.

You will only see a box that protects those parts from water and other harmful substances.

No doubt, the advancement in the automobile industry has made it possible to manufacture waterproof parts. But with such improvement, the cost of cars touches the sky as well.

That’s why people don’t seem to care about the damage done by the unguided car wash and spraying water on the engine bay.

High-Pressure Water for Car Wash

Now, you must have seen how the car service stations carry out the car wash job. They use a high-pressure water spray to clean the engine bay. Is that the right method?

If you directly spray the engine bay of your car with high-pressure water, the chances are that it might damage your car’s critical components. These components include:

  • Alternator
  • Electronic Sensors
  • Spark Plug
  • Lights

You already know these parts either work electrically or electronically. Therefore, it’s not a wise option to directly spray water on these parts without covering them.

How to Cover Critical Auto Parts During Car Wash?

Now, once you have decided to wash your car, there are a few things you have to take care of.

First, cover the engine’s critical components.

If you are wondering why the automobile service stations don’t follow this step, you are thinking right.

The car washing crew has no problem washing your car with the critical parts covered or not at the service station. They wash hundreds of cars in a month. That’s why they keep an eye on where to give maximum water pressure and where to keep the pressure low.

So, if you are willing to wash your car on your own, it’s mandatory to cover the following parts in the engine bay.

Air FIlter

If your car’s air filter is exposed, make sure you cover that properly before spraying water on it.

The air filter directly connects to your car’s engine. So if it’s exposed and you spray water on that, there’s a high chance that the water will find its way into the engine. Do you know what that means? Hydro locking.


Hydrostatic locking (hydro locking) is when the water or any other substance gets on top of the piston. Inside an engine, the piston keeps on moving up and down. Once water gets there, the road inside the engine might get bent. Result? Engine failure.

On top of that, you might have to replace your car’s engine, which is not an ordinary expense.

Therefore, cover your car’s air filter first with a plastic sheet or any other steady material.

Check out the Purolator Air Filter for a high volume of clean air.


An alternator is responsible for converting mechanical energy into electrical energy.

The alternator is an important part of your car. Without that, your car’s battery won’t get a sufficient amount of current.

So it’s better to cover the alternator before washing your car’s engine bay.

However, you might not face any bigger consequences if the alternator gets wet. But it’s better to keep the electrical processes away from water for a safe and smooth experience.

You can cover your car’s alternator using a completely sealed box made of plastic.

Serpentine Belt

The serpentine belt is important for your car’s movement. Your car can’t move if the belt is broken.

However, water or other lubricants don’t affect the performance of the serpentine belt. Instead, the belt squeals once it faces friction.

But the point here is to avoid directly spraying the belt with high pressure. It’s the force of the water that will damage the belt, not the water itself.

Have a look at the Goodyear Serpentine Belts to maximize your engine’s operation.


The wiring inside your car’s engine bay is highly vulnerable to high-pressure water spray. Especially if you have customized automobile or aftermarket wiring installed in your vehicle, you might have to be more careful.


You already know that the aftermarket wiring is not as stable as the original one. This is because the car manufacturers use cutting-edge technology to seal the wiring on terminals and connecting points. Moreover, some of the sensors are sealed in a box as well.

But when a person modifies the car and makes some tweaks in the engine bay, those wiring might get disturbed.

Apparently, you can’t observe the difference. All the wiring looks intact. Especially the joints and terminals. However, the modification might have weakened those electrical connections.

The terminal points are now also exposed to water. Some of the major wiring points are:

  • Relays
  • Connectors
  • Fuse Boxes

Therefore, never spray high-pressure water on the wiring. You must cover the connections prior to washing your car. But to avoid any bigger trouble, just don’t spray water on the wires.

Now that you have taken the necessary safety measures let’s see how to wash your car’s engine bay.

Clean Your Car’s Engine Bay

Cleaning the car’s engine bay is simple. The only thing which makes it complicated is the type of your car’s engine.


Old-School Engines

If you got a vintage model from the pre-’90s, your car might have more mechanical components. In that case, first, make sure that the temperature of the engine bay is touch-friendly.

Almost all the mechanical components use metal objects. If the metal is hot and you spray water on it, that metallic part might get damaged. How?

The metal expands on heating and contracts on cooling. So when you pour cold or even mild-temperature water on a hot piece of metal, the piece will contract.

Talking about the engine bay, each component is designed for a specific purpose. All the metallic components are of fixed shape and size.

Therefore, if the contraction or expansion occurs, you never know which area of your car’s engine will suffer.

New Engines

The modern car engines are safer to wash. The car manufacturers keep the critical components inside a water-resistant protective box.

Therefore, you only have to avoid spraying water on the electrical and electronic components with high pressure.

Use a Garden Hose to Pre-Rinse

First, shower water on the engine bay using a garden hose. The garden hose has a normal water pressure, which will not damage any part of the engine.

Prepare the Cleaner

Prepare all the accessories to wash your car. Keep them near you in a bucket as you might have to switch between the cleaners.

Focus on Top of Engine Bay

The top components inside the engine usually get more dirt. Therefore, target them first and clean them thoroughly. The sides of the engine’s auto parts might be difficult to wash. Just spray water there and wait till the engine dries off.

Moreover, you can start your engine to hasten the drying process. The temperature and vibration will help water evaporate quickly.

Final Touch

Add up some dressing on your engine. This will give it a more natural look and protect it from severe dryness.

The dressings also make the car’s engine look new and fresh. After that, you are ready to go with your cleaned-up car engine.


Washing your car’s engine is an easy job. First, however, you have to check a few things like the type of engine and exposed wiring before spraying water on the engine.

It’s safe to spray water on your engine if it’s not high in temperature. You have to wait till the engine cools down. After that, you can spray water on it and clean it thoroughly. That will make the engine look clean, just like a new one.

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